The most common construction of a personal computer is a stand-alone desk-type computer using magnetic disk drives. Such computers, for example the Apple MacIntosh computer, utilize a relatively large one-piece casing and significant power. This type of construction cannot be employed in so-called lap-type computers, let alone in an extremely small pocket-type computer. Such lap-type and pocket-type computers normally utilize memory cards and other miniature electronic components. So as to accommodate a display screen lap-type and pocket-type computers have employed a two-piece or multi-piece housing or casing with an upper casing containing the display screen.
In these devices each incremental part of the internal casing inch volume is important so to accommodate the required components. For example, the Zenith SupersPort 286 Model includes a multi-piece casing in which a hinged upper casing incorporates a viewing screen and contains a pair of slidable hook-type latches in relatively wide side margins which depend outwardly from the upper casing. A lower casing from which a computer keyboard projects has side margins corresponding to the side margins of the upper casing and a pair of apertures to receive the hook-type latches. A suitable latch keeper and pairs of movable latching members are mounted within these side margins and co-act with cam surfaces on the latches to lock the casings together when the casings are pivoted into abutment to the container "closed" condition. Ribbed switch-type operators extend from the exterior of the casing and are accessed from the exterior of the upper casing side margins to release the latch hooks from the keeper and to allow hinged movement of the upper casing to a container "open" condition where the keyboard can be accessed and the screen observed by the user. Both side margins are relatively wide (i.e. about 10 millimeters) to accommodate these various latch elements.
Many other two-part general usage containers have an integral latch plate extending and accessed from the exterior of a bottom casing with a latch tab member extending downwardly from an exterior edge portion of an upper casing so that as the latch tab member is slid into engagement with lips on either side of a latch keeper, the latch member engages the keeper and latches the casings in a closed condition. Pulling the tab member outwardly releases the lock action and the tab member is slid upwardly from the lips to allow the casings to be in an "open" condition.
In another commercial computer product, the CASIO Digital Diary calculator and memory unit, a two-piece casing includes a depending latch inboard of the upper casing sidewall and an aperture bridging a keyboard and the sidewall of the lower casing. It appears that the sidewalls, including the latch mechanisms in this construction, are about 5 mm in width.